They get away with this crap because they know full well that most people will not fight it. If people did, then it would be cheaper for them to give you the benefit of the doubt. That said, look carefully at your policy to see whether you will win.
The fact that your daughter was not legally at fault does not mean that a defensive driver would not have avoided the accident. If their standards are based on whether it was avoidable, then the fact that you were legally doing the right thing in the right place does not necessarily mean that you'll win this judgement.
The other thing to look at is what this means for your daughter's premiums. Is it possible that if she accepts some responsibility for the accident, that her premiums will go up more? If so, then you could be talking a lot more than $200-$300!
Cheers,
Ben